1. 以what等连接代词引导的主语从句

What you need is more practice. 你需要的是更多的练习。

Whoever wants it may have it. 谁要都可以给他。

同类的连接代词还有：What， who， whom， whose， which， whatever， whoever， whichever

2. 以that， whether从属连词引导的主语从句

It was strange that he had made a mistake. 真奇怪，他竟然错了。

That we need more equipment is quite obvious. 我们需要更多的设备，这是很明显的。

Whether he will join us won't make too much difference.

他是否加入我们，没有太大的差别。

3. 主语从句的引导词that什么时候可以省略

当主语从句不太长时，引导词“that”可以省略

It's clear (that) he has done his best. 很明显他已经尽力而为了。

It's a wonder (that) he didn't fail. 真奇怪，他没有失败。

4. 以when等连接副词引导的主语从句

When they will come hasn't been made public. 他们什么时候来还没有公布。

Where she has gone is not known yet. 她去了哪儿，还不知道。

Why he did it will remain a puzzle for ever. 为什么他做那件事将永远是个谜团。